This view of the twilight sky and Martian horizon taken by NASA's Curiosity Mars rover includes Earth as the brightest point of light in the night sky. Earth is a little left of center in the image, and our moon is just below Earth.

This frame from an animation from NASA's Mars rover Curiosity shows the rover drilling into rock target 'Cumberland.' The drilling was performed during the 279th Martian day, or sol, of the Curiosity's work on Mars (May 19, 2013).

This image from the Mars Hand Lens Imager on NASA's Mars rover Curiosity shows the patch of rock cleaned by the first use of the rover's Dust Removal Tool (DRT). The tool is a motorized, wire-bristle brush on the turret at the end of the rover's arm.

The two bodies in this portion of an evening-sky view by NASA's Mars rover Curiosity are Earth and Earth's moon. The rover's Mast Camera (Mastcam) imaged them in the twilight sky of Curiosity's 529th Martian day, or sol (Jan. 31, 2014).

This map shows the route that NASA's Curiosity Mars rover drove inside Gale Crater from its landing in August 2013 through Jan. 26, 2004. The rover is approaching a gap between two low scarps, 'Dingo Gap.'

As the Sample Analysis at Mars (SAM) suite of instruments on NASA's Curiosity Mars rover heats a sample, gases are released (or 'evolved') from the sample and can be identified using SAM's quadrupole mass spectrometer.

Measurements with the MSL's RAD on NASA's Curiosity Mars rover during the flight to Mars and now on the surface of Mars enable an estimate of the radiation astronauts would be exposed to on an expedition to Mars.

This illustration shows the instruments and subsystems of the Sample Analysis at Mars (SAM) suite on the Curiosity Rover of NASA's Mars Science Laboratory Project. SAM analyzes the gases in the Martian atmosphere.

The Dynamic Albedo of Neutrons (DAN) instrument on NASA's Mars rover Curiosity took measurement on a rock outcrop (Spot 39) and on loose soil (Spot 40) within the 'Yellowknife Bay' area of Mars' Gale Crater.

This series of images reconstructs the geology of the region around Mars' Mount Sharp, where NASA's Curiosity Mars rover landed and is now driving. The images were taken on Earth and have been altered for the illustration.

This graph based on data from the RAD instrument onboard NASA's Mars Science Laboratory spacecraft shows the flux of energetic particles (vertical axis) as a function of the estimated energy deposited in water (horizontal axis).

This schematic shows the atomic structure of the smallest units that make up the layers and interlayer region of clay minerals. This structure is similar to the clay mineral in drilled rock powder collected by NASA's Curiosity Mars rover.

This map shows where NASA's Mars rover Curiosity landed in August 2012 at 'Bradbury Landing.' All of these features are inside Gale Crater. Curiosity's next major destination, the entry point to the base of Mount Sharp.

This frame from an animation of NASA's Curiosity rover shows the complicated suite of operations involved in conducting the rover's first rock sample drilling on Mars and transferring the sample to the rover's scoop for inspection.

On this image of the broken rock called 'Tintina,' color coding maps the amount of mineral hydration indicated by a ratio of near-infrared reflectance intensities measured by the Mastcam on NASA's Mars rover Curiosity.

This graphic compares the radiation dose equivalent for several types of experiences, including a calculation for a trip from Earth to Mars based on measurements made by the RAD instrument shielded inside NASA's Mars Science Laboratory spacecraft.

This mosaic of nine images taken at a location called 'Darwin,' inside Gale Crater, were taken by NASA's Mars rover Curiosity and shows detailed texture in a conglomerate rock bearing small pebbles and sand-size particles.

This is a version of one of the first images taken by a rear Hazard-Avoidance camera on NASA's Curiosity rover and shows part of the rim of Gale Crater, which is a feature the size of Connecticut and Rhode Island combined.

This diagram shows how materials analyzed by the ChemCam instrument on NASA's Curiosity Mars rover during the first 100 Martian days of the mission differed with regard to hydrogen content (horizontal axis) and alkali (vertical axis).